I would give Cyrax top 3, but not #1. Kabal is the undisputed best. In my opinion Kabal has no 5-5 match-ups besides the mirror match; he beats Kung Lao 6-4, Cyblax 6-4, Kitana 6-4, Reptile 6-4, and beats every other character in the game I didn't mention 7-3 or worse.
Honestly DJT played amazing, REO played amazing, they are both possibly top Cyrax and top Kabal respectively. But in my honest opinion, Cyrax and Kabal aren't even near being played to their highest potential yet. This game is still being fleshed out, and we are starting to see that now ever since last Friday. Human error keeps us from playing Kabal and Cyrax at the highest possible level, it is too hard to have the perfect execution you need at all times to be playing these two characters at the highest possible level.
Kabal being played at the highest possible level:
Your IAGB are perfect. You can IAGB so fast and so low to the ground that your opponent can't even dash block to get in. They have to walk crouch, walk crouch, walk crouch. Because dashing will cause you to get hit in the face by a gas blast. You have to be able to 2~NDC block infinite big hitbox characters, and also need to be able to mixup the block infinite with things such as B1~EX NDC and F32~EX NDC. Playing Kabal at the highest possible level means that your zoning is so perfect that by the time your opponent gets next to you, you already have a full bar of meter. And you can use that meter to EX Nomad Dash and EX NDC. EX Nomad Dash/NDC stops cross overs, stops jump ins, stops rushdown, stops zoning. It literally does everything. You can even use EX NDC to pressure your opponent and have enough frame advantage to guarantee that they have to block your next attack. You need to pressure your opponent all day and use mix-ups until you eventually guess right with low buzz saw or hookswords. Any time you connect with low buzz saw or hookswords = a hard knockdown, and any time Kabal gets a hard knockdown you can zone until you have full bar of meter again. Not to mention Kabal has 40% meterless BnB's that end in F4 standing reset, in which you can start pressuring your opponent, mix them up, or just start zoning for your full bar of meter again. When Kabal plays perfectly, he is literally untouchable.
Cyrax being played at highest possible level:
Everytime you touch your opponent, it is a 100% combo. Tony-T showed combos where if you shoot a net from full screen and it catches your opponent, you can teleport to them and get a 100%. Whether the net caught them in the air or on the ground. Also Cyrax has like unbreakable 70% combos I believe. Hell I even seen Cyrax combos posted on this website that were like 60% meterless. So that means if Cyrax is being played perfectly at the highest possible level with no human error or no mistakes, you opponent loses his whole life bar every single time he is caught in a net, whether the net catches you grounded or airborne, sweep distance or full-screen, it doesn't even matter. And if Cyrax has meter, he can do anywhere between 40%-70% unbreakable combos. That means you can't even save yourself with your breaker. Also let's not forget his EX net. Let's take this situation for example. Let's say this was a real tournament match. Kung Lao vs Cyrax. Kung Lao has a 100% life with one bar of meter, Cyrax has 1% life 2 bars of meter. Kung Lao decides to chip out Cyrax with a dive kick. The dive kick wasn't enough, Cyrax blocks the dive kick. 21~EX net..... Now Cyrax just did a 100% combo with 1 bar of meter and Kung Lao is dead, he couldn't get a breaker in time to stop the combo. That is some shit that could legitimately happen in a real match. That is fucked up lol.
^^^
Nobody is playing Cyrax or Kabal like this yet, and when people do start playing Cyrax and Kabal like this every single other character in the game is pretty much going to become obsolete. But like I said, human error prevents people from playing Cyrax and Kabal like this, so it will probably never happen. Humans make mistakes, humans mess up inputs and humans drop combos.